Disclaimer: These guidelines were developed under contract using generally accepted secondary sources. The protocol used by the contractor for surveying these data sources was developed by the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA), and the Department of Energy (DOE). The information contained in these guidelines is intended for reference purposes only. None of the agencies have conducted a comprehensive check of the information and data contained in these sources. It provides a summary of information about chemicals that workers may be exposed to in their workplaces. The secondary sources used for supplements 111 and 1V were published before 1992 and 1993, respectively, and for the remainder of the guidelines the secondary sources used were published before September 1996. This information may be superseded by new developments in the field of industrial hygiene. Therefore readers are advised to determine whether new information is available.

OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR COAL DUST (GREATER THAN OR EQUAL TO 5 PERCENT SiO(2))

INTRODUCTION

This guideline summarizes pertinent information about coal dust for workers and employers as well as for physicians, industrial hygienists, and other occupational safety and health professionals who may need such information to conduct effective occupational safety and health programs. Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new information is available.

SUBSTANCE IDENTIFICATION

* Formula

Not applicable.

* Structure

(For Structure, see paper copy)

* Synonyms

Sea coal, coal facings, ground bituminous coal, anthracite coal dust, lignite coal dust [Sittig 1991, p. 450; NIOSH 1994a]

* Identifiers

1. CAS No.: None.

2. RTECS No.: GF8281000 [NIOSH 1995; NIOSH 1994a]

3. DOT UN: 1361 32 [Sittig 1991, p. 450; DOT 1993]

4. DOT label: Flammable solid [Genium 1990]

* Appearance and odor

Coal dust is an odorless dark brown to black dust created by the crushing, grinding, or pulverizing coal. The coal dust covered by this document contains 5 percent or more free silica [Sittig 1991, p. 450; Genium 1990].

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

The physical properties of this coal dust vary depending on the specific type of coal.

1. Molecular weight: Varies.

2. Boiling point: Varies.

3. Specific gravity: Varies.

4. Vapor density: Not applicable.

5. Melting/Freezing point: Varies.

6. Vapor pressure: Not applicable.

7. Solubility: Varies.

8. Evaporation rate: Not applicable.

* Reactivity

1. Conditions contributing to instability: Heat, sparks, open flame, or other ignition sources [Genium 1990; Sittig 1991, p. 450].

2. Incompatibilities: None reported.

3. Hazardous decomposition products: None reported.

4. Special precautions: None reported.

* Flammability

The National Fire Protection Association has not assigned a flammability rating to coal dust. Other sources rate coal dust as a fire hazard and consider the airborne dust an explosion hazard when these substances are exposed to heat or open flame [Genium 1990].

1. Flash point: Data not available.

2. Autoignition temperature: >601 degrees C (>1114 degrees F)-cloud; >200 degrees C (>392 degrees F)-layer [Genium 1990]

3. Flammable limits in air: >0.05 oz./ft(3) [Genium 1990]

4. Extinguishant: For small fires use dry chemical, sand, earth, water spray, or regular foam. Use water spray, fog, or regular foam to fight large fires involving coal dust [DOT 1993, Guide 32].

Fires involving coal dust should be fought upwind from the maximum distance possible. Keep unnecessary people away; isolate the hazard area and deny entry. For a massive fire in a cargo area, use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from the area and let the fire burn. Emergency personnel should stay out of low areas. Containers of coal dust should be moved from the fire area if it is possible to do so safely. If this is not possible, cool fire exposed containers from the sides with water until well after the fire is out. Stay away from the ends of containers. Firefighters should wear a full set of protective clothing and self-contained breathing apparatus when fighting fires involving coal dust [DOT 1993, Guide 32].

EXPOSURE LIMITS

* OSHA PEL

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for the respirable fraction of coal dust (greater than or equal to 5 percent silica) is 10 milligrams per cubic meter (mg/m(3)) / % SiO(2) + 2 as an 8-hour time-weighted average (TWA) concentration [29 CFR 1910.1000, Table Z-3].

* NIOSH REL

* The National Institute for Occupational Safety and Health has not established a recommended exposure limit for coal dust.

* ACGIH TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned the respirable fraction of coal dust containing greater than 5 percent crystalline silica a threshold limit value (TLV) of 0.1 mg/m(3) (for respirable quartz) as a TWA for a normal 8-hour workday and a 40-hour workweek [ACGIH 1994, p. 17].

* Rationale for Limits

The ACGIH limit is based on the risk of pneumoconiosis [ACGIH 1991, p. 326].

HEALTH HAZARD INFORMATION

* Routes of Exposure

Exposure to coal dust can occur through inhalation, ingestion, and eye contact.

* Summary of toxicology

1. Effects on Animals: Coal dust is a tumorigenic agent in experimental animals. Coal dusts were shown to be equivocal tumorigenic agents associated with lymphomas and, at the higher dose, adrenal cortex tumors in rats exposed to either 6.6 or 14.9 mg/m(3) for 6 hours/day intermittently for 86 weeks [NIOSH 1991]. The American Conference of Governmental Industrial Hygienists (ACGIH) considers the toxicity of coal dust with greater than 5 percent silica to be similar to quartz [ACGIH 1991].

2. Effects on Humans: Coal dust causes pneumoconiosis, bronchitis and emphysema in exposed workers. Coal dust causes coal workers' pneumoconiosis (CWP) and progressive massive fibrosis [Hathaway et al. 1991; Rom 1992]. Simple CWP is characterized by development of coal macules, a focal collection of dust laden macrophages with associated reticulin deposits and focal emphysema [Rom 1992]. These lesions may be visible as small opacities (less than 1 cm in diameter) on X-rays [Hathaway et al. 1991]. Complicated CWP is characterized by lesions consisting of a mass of rubbery well defined black tissue that is often adherent to the chest wall. CWP mat be associated with decrements in ventilatory capacity, low diffusing capacity, abnormalities of gas exchange, and premature death. The disease may progress after the cessation of exposure. In X-ray examinations, opacities greater than 1 cm in diameter may be observed [Hathaway et al. 1991]. Coal dust is also recognized as a cause of chronic bronchitis [Rom 1992]. Exposure to coal dust is associated with an increased risk of focal emphysema, which is usually associated with the presence of pneumoconiosis and centrilobular emphysema, which can occur in the absence of pneumoconiosis [Rom 1992]. Workers with rheumatoid arthritis and the simple coalworkers' pneumoconiosis may also have Caplan's Syndrome which involves rapidly developing lung damage [Genium 1990]. ACGIH considers the toxicity of coal dust with greater than 5 percent silica to be similar to quartz [ACGIH 1991].

* Signs and symptoms of exposure

1. Acute exposure: Symptoms of inhalation of excessive amounts of coal dust include coughing, wheezing, and shortness of breath [Genium 1990].

2. Chronic exposure: Chronic exposure to coal dust may result in symptoms of bronchitis and emphysema [Rom 1992].

EMERGENCY MEDICAL PROCEDURES

* Emergency medical procedures: [NIOSH to supply]

5. Rescue: Remove an incapacitated worker from further exposure and implement appropriate emergency procedures (e.g., those listed on the Material Safety Data Sheet required by OSHA's Hazard Communication Standard [29 CFR 1910.1200]). All workers should be familiar with emergency procedures, the location and proper use of emergency equipment, and methods of protecting themselves during rescue operations.

EXPOSURE SOURCES AND CONTROL METHODS

The following operations may involve coal dust and lead to worker exposures to this substance:

* The mining and transportation of coal

* Use of coal during operations involving grinding, crushing, or pulverizing

Methods that are effective in controlling worker exposures to coal dust, depending on the feasibility of implementation, are as follows:

* Process enclosure
* Local exhaust ventilation
* General dilution ventilation
* Personal protective equipment

Workers responding to a release or potential release of a hazardous substance must be protected as required by paragraph (q) of OSHA's Hazardous Waste Operations and Emergency Response Standard [29 CFR 1910.120].

Good sources of information about control methods are as follows:

1. ACGIH [1992]. Industrial ventilation--a manual of recommended practice. 21st ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

2. Burton DJ [1986]. Industrial ventilation--a self study companion. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

3. Alden JL, Kane JM [1982]. Design of industrial ventilation systems. New York, NY: Industrial Press, Inc.

4. Wadden RA, Scheff PA [1987]. Engineering design for control of workplace hazards. New York, NY: McGraw-Hill.

5. Plog BA [1988]. Fundamentals of industrial hygiene. Chicago, IL: National Safety Council.

MEDICAL SURVEILLANCE

OSHA is currently developing requirements for medical surveillance. When these requirements are promulgated, readers should refer to them for additional information and to determine whether employers whose employees are exposed to coal dust are required to implement medical surveillance procedures.

* Medical Screening

Workers who may be exposed to chemical hazards should be monitored in a systematic program of medical surveillance that is intended to prevent occupational injury and disease. The program should include education of employers and workers about work-related hazards, early detection of adverse health effects, and referral of workers for diagnosis and treatment. The occurrence of disease or other work-related adverse health effects should prompt immediate evaluation of primary preventive measures (e.g., industrial hygiene monitoring, engineering controls, and personal protective equipment). A medical surveillance program is intended to supplement, not replace, such measures. To detect and control work-related health effects, medical evaluations should be performed (1) before job placement, (2) periodically during the term of employment, and (3) at the time of job transfer or termination.

* Preplacement medical evaluation

Before a worker is placed in a job with a potential for exposure to coal dust, a licensed health care professional should evaluate and document the worker's baseline health status with thorough medical, environmental, and occupational histories, a physical examination, and physiologic and laboratory tests appropriate for the anticipated occupational risks. These should concentrate on the function and integrity of the respiratory system [Sittig 1991, p. 450]. Medical surveillance for respiratory disease should be conducted using the principles and methods recommended by the American Thoracic Society [ATS 1987].

A preplacement medical evaluation is recommended to assess medical conditions that may be aggravated or may result in increased risk when a worker is exposed to coal dust at or below the prescribed exposure limit. The health care professional should consider the probable frequency, intensity, and duration of exposure as well as the nature and degree of any applicable medical condition. Such conditions (which should not be regarded as absolute contraindications to job placement) include a history and other findings consistent with diseases of the respiratory system [Sittig 1991, p. 450].

* Periodic medical evaluations

Occupational health interviews and physical examinations should be performed at regular intervals during the employment period, as mandated by any applicable Federal, State, or local standard. Where no standard exists and the hazard is minimal, evaluations should be conducted every 3 to 5 years or as frequently as recommended by an experienced occupational health physician. Additional examinations may be necessary if a worker develops symptoms attributable to coal dust exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of coal dust on the respiratory system [Sittig 1991, p. 450]. Current health status should be compared with the baseline health status of the individual worker or with expected values for a suitable reference population.

* Termination medical evaluations

The medical, environmental, and occupational history interviews, the physical examination, and selected physiologic or laboratory tests that were conducted at the time of placement should be repeated at the time of job transfer or termination to determine the worker's medical status at the end of his or her employment. Any changes in the worker's health status should be compared with those expected for a suitable reference population. Because occupational exposure to coal dust may cause diseases with prolonged latent periods, the need for medical surveillance may extend well beyond the termination of employment [Sittig 1991, p. 450].

* Biological monitoring

Biological monitoring involves sampling and analyzing body tissues or fluids to provide an index of exposure to a toxic substance or metabolite. No biological monitoring test acceptable for routine use has yet been developed for coal dust.

WORKPLACE MONITORING AND MEASUREMENT

Determination of a worker's exposure to airborne the respirable fraction of coal dust containing greater than 5 percent silica is made using a tared low ash polyvinyl chloride (LAPVC) filter (5 microns), preceded by a 10 mm cyclone. Samples are collected at a maximum flow rate of 1.7 liters/minute until a maximum collection volume of 816 liters is reached. Analysis is conducted by gravimetric analysis (weighing). This method is described in the OSHA Computerized Information System [OSHA 1994] and is fully validated. NIOSH has also published a similar method (Method No. 7603) for respirable sampling of silica in coal mine dust that requires analysis by infrared spectroscopy [NIOSH 1994b].

PERSONAL HYGIENE PROCEDURES

If coal dust contacts the skin, workers should wash the affected areas with soap and water [Genium 1990].

Clothing contaminated with coal dust should be removed immediately, and provisions should be made for the safe removal of the chemical from the clothing. Persons laundering the clothes should be informed of the hazardous properties of coal dust.

A worker who handles coal dust should thoroughly wash hands, forearms, and face with soap and water before eating, using tobacco products, using toilet facilities, applying cosmetics, or taking medication [Genium 1990].

Workers should not eat, drink, use tobacco products, apply cosmetics, or take medication in areas where coal dust handled, processed, or stored [Genium 1990].

STORAGE

In the event coal dust requires storage, it should be stored in a cool, dry, well-ventilated area in tightly sealed containers that are labeled in accordance with OSHA's Hazard Communication Standard [29 CFR 1910.1200]. Containers of coal dust should be protected from physical damage and ignition sources and should be stored separately from oxidizing agents [Genium 1990].

SPILLS AND LEAKS

In the event of a spill or leak involving coal dust, persons not wearing protective equipment and clothing should be restricted from contaminated areas until cleanup has been completed. The following steps should be undertaken following a spill or leak:

1. Do not touch the spilled material.

2. Notify safety personnel.

3. Remove all sources of heat and ignition.

4. Use non-sparking tools.

5. Water spray may be used cautiously to wet down the coal dust to reduce raising dust.

6. Collect the spilled material and place the material into a covered metal container for disposal or reclamation [Genium 1990].

SPECIAL REQUIREMENTS

U.S. Environmental Protection Agency (EPA) requirements for emergency planning, reportable quantities of hazardous releases, community right-to-know, and hazardous waste management may change over time. Users are therefore advised to determine periodically whether new information is available.

* Emergency planning requirements

Coal dust is not subject to EPA emergency planning requirements under the Superfund Amendments and Reauthorization Act (SARA) (Title III) in 42 USC 11022.

* Reportable quantity requirements for hazardous releases

A hazardous substance release is defined by EPA as any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment (including the abandonment or discarding of contaminated containers) of hazardous substances. In the event of a release that is above the reportable quantity for that chemical, employers are required to notify the proper Federal, State, and local authorities [40 CFR 355.40].

Employers are not required by the emergency release notification provisions in 40 CFR Part 355.40 to notify the National Response Center of an accidental release of coal dust; there is no reportable quantity for this substance.

* Community right-to-know requirements

Employers are not required by EPA in 40 CFR Part 372.30 to submit a Toxic Chemical Release Inventory form (Form R) to EPA reporting the amount of coal dust emitted or released from their facility annually.

* Hazardous waste management requirements

EPA considers a waste to be hazardous if it exhibits any of the following characteristics: ignitability, corrosivity, reactivity, or toxicity as defined in 40 CFR 261.21-261.24. Under the Resource Conservation and Recovery Act (RCRA) [40 USC 6901 et seq.], EPA has specifically listed many chemical wastes as hazardous. Although coal dust is not specifically listed as a hazardous waste under RCRA, EPA requires employers to treat waste as hazardous if it exhibits any of the characteristics discussed above.

Providing detailed information about the removal and disposal of specific chemicals is beyond the scope of this guideline. The U.S. Department of Transportation, EPA, and State and local regulations should be followed to ensure that removal, transport, and disposal of this substance are conducted in accordance with existing regulations. To be certain that chemical waste disposal meets EPA regulatory requirements, employers should address any questions to the RCRA hotline at (703) 412-9810 (in the Washington, D.C. area) or toll-free at (800) 424-9346 (outside Washington, D.C.). In addition, relevant State and local authorities should be contacted for information on any requirements they may have for the waste removal and disposal of this substance.

RESPIRATORY PROTECTION

* Conditions for respirator use

Good industrial hygiene practice requires that engineering controls be used where feasible to reduce workplace concentrations of hazardous materials to the prescribed exposure limit. However, some situations may require the use of respirators to control exposure. Respirators must be worn if the ambient concentration of coal dust exceeds prescribed exposure limits. Respirators may be used (1) before engineering controls have been installed, (2) during work operations such as maintenance or repair activities that involve unknown exposures, (3) during operations that require entry into tanks or closed vessels, and (4) during emergencies. Workers should only use respirators that have been approved by NIOSH and the Mine Safety and Health Administration (MSHA).

* Respiratory protection program

Employers should institute a complete respiratory protection program that, at a minimum, complies with the requirements of OSHA's Respiratory Protection Standard [29 CFR 1910.134]. Such a program must include respirator selection, an evaluation of the worker's ability to perform the work while wearing a respirator, the regular training of personnel, respirator fit testing, periodic workplace monitoring, and regular respirator maintenance, inspection, and cleaning. The implementation of an adequate respiratory protection program (including selection of the correct respirator) requires that a knowledgeable person be in charge of the program and that the program be evaluated regularly. For additional information on the selection and use of respirators and on the medical screening of respirator users, consult the latest edition of the NIOSH Respirator Decision Logic [NIOSH 1987b] and the NIOSH Guide to Industrial Respiratory Protection [NIOSH 1987a].

PERSONAL PROTECTIVE EQUIPMENT

Workers should use appropriate personal protective clothing and equipment that must be carefully selected, used, and maintained to be effective in preventing skin contact with coal dust. The selection of the appropriate personal protective equipment (PPE) (e.g., gloves, sleeves, encapsulating suits) should be based on the extent of the worker's potential exposure to coal dust. There are no published reports on the resistance of various materials to permeation by coal dust.

To evaluate the use of PPE materials with coal dust, users should consult the best available performance data and manufacturers' recommendations. Significant differences have been demonstrated in the chemical resistance of generically similar PPE materials (e.g., butyl) produced by different manufacturers [Mickelsen and Hall 1987]. In addition, the chemical resistance of a mixture may be significantly different from that of any of its neat components [Mickelsen et al. 1986].

Any chemical-resistant clothing that is used should be periodically evaluated to determine its effectiveness in preventing dermal contact. Safety showers and eye wash stations should be located close to operations that involve coal dust.

Splash-proof chemical safety goggles or face shields (20 to 30 cm long, minimum) should be worn during any operation in which a solvent, caustic, or other toxic substance may be splashed into the eyes.

In addition to the possible need for wearing protective outer apparel (e.g., aprons, encapsulating suits), workers should wear work uniforms, coveralls, or similar full-body coverings that are laundered each day. Employers should provide lockers or other closed areas to store work and street clothing separately. Employers should collect work clothing at the end of each work shift and provide for its laundering. Laundry personnel should be informed about the potential hazards of handling contaminated clothing and instructed about measures to minimize their health risk.

Protective clothing should be kept free of oil and grease and should be inspected and maintained regularly to preserve its effectiveness.

Protective clothing may interfere with the body's heat dissipation, especially during hot weather or during work in hot or poorly ventilated work environments.

REFERENCES

ACGIH [1991]. Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ACGIH [1994]. 1994-1995 Threshold limit values for chemical substances and physical agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ATS [1987]. Standardization of spirometry -- 1987 update. American Thoracic Society. Am Rev Respir Dis 136:1285-1296.

CFR. Code of Federal regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Register.

DOT [1993]. 1993 Emergency response guidebook, guide 32. Washington, DC: U.S. Department of Transportation, Office of Hazardous Materials Transportation, Research and Special Programs Administration.

Genium [1990]. Material safety data sheet No. 491. Schenectady, NY: Genium Publishing Corporation.

Hathaway GJ, Proctor NH, Hughes JP, and Fischman ML [1991]. Proctor and Hughes' chemical hazards of the workplace. 3rd ed. New York, NY: Van Nostrand Reinhold.

Mickelsen RL, Hall RC [1987]. A breakthrough time comparison of nitrile and neoprene glove materials produced by different glove manufacturers. Am Ind Hyg Assoc J 48(11): 941-947.

Mickelsen RL, Hall RC, Chern RT, Myers JR [1991]. Evaluation of a simple weight-loss method for determining the permeation of organic liquids through rubber films. Am Ind Hyg Assoc J 52(10): 445-447.

NIOSH [1987a]. NIOSH guide to industrial respiratory protection. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-116.

NIOSH [1987b]. NIOSH respirator decision logic. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-108.

NIOSH [1991]. Registry of toxic effects of chemical substances: Coal, ground bituminous. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Division of Standards Development and Technology Transfer, Technical Information Branch.

NIOSH [1994a]. NIOSH pocket guide to chemical hazards. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-116.

NIOSH [1994b]. NIOSH manual of analytical methods. 4th ed. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113.

NIOSH [1995]. Registry of toxic effects of chemical substances: Coal, ground bituminous. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Division of Standards Development and Technology Transfer, Technical Information Branch.

OSHA [1994]. Computerized information system. Washington, DC: U.S. Department of Labor, Occupational Safety and Health Administration.

Rom WN [1992]. Environmental and occupational medicine. 2nd ed. Boston, MA: Little, Brown and Company.

Sittig M [1991]. Handbook of toxic and hazardous chemicals. 3rd ed. Park Ridge, NJ: Noyes Publications.

USC. United States code. Washington. DC: U.S. Government Printing Office.